1. Field of the Invention
The present invention relates to a golf club head having a score line groove.
2. Description of the Related Art
A score line groove is formed on many golf club heads. The score line groove can contribute to an increase in a backspin rate.
Japanese Patent Application Laid-Open No. 9-253250 discloses a head having a small groove formed on a face surface. The small groove is formed by utilizing a cutting trace when forming the face surface.
Japanese Patent Application Laid-Open No. 2002-153575 discloses a recessed part formed on a face surface by microfabrication. The depth of the recessed part is 5 to 10 μm, and the width of the recessed part is 5 to 20 μm.
Japanese Patent Application Laid-Open No. 2007-202633 discloses a head having a small groove formed on a face part. The small groove has an opening width and a depth less than those of a score line.
Japanese Patent Application Laid-Open No. 2008-132168 (US2008/0125242, US2009/0312116, US2010-0261545) discloses a head including a plurality of score line grooves and a plurality of thin grooves. An angle between the thin groove and the score line groove is set to 40 degrees or greater and 70 degrees or less as viewed clockwise from the toe side of the score line groove.
Japanese Patent Application Laid-Open No. 2010-88678 (US2010-0087270) discloses a head including a plurality of thin grooves extending to a heel side from a toe side.
Japanese Patent Application Laid-Open No. 2011-234748 (US2011-0269568) discloses a head having thin groove formed parallel to score line in each region between the adjacent score lines.
Japanese Patent Application Laid-Open No. 2011-234749 (US2011-0269567) discloses a head having a plurality of score lines, a first thin groove, and a second thin groove formed on a face surface. The first thin groove is parallel to the score line. The second thin groove crosses the score line.
Japanese Patent Application Laid-Open No. 2008-23178 (US2008/0020859, US2009/0176597, US2011-0081985, US2011-0086725) discloses a face surface having a circular cutting trace formed by mealing processing, and an S-shaped cutting trace.
Japanese Patent Application Laid-Open No. 2008-272271 discloses many small groove lines which are shallower than a score line groove and have a width narrower than that of the score line groove. The gazette discloses that the small groove lines are curves protruded to a top side.